1. Field of the Invention
The present invention relates to a composition for accelerating wound healing comprising as an effective ingredient a compound represented by general formula (I): ##STR2## wherein R.sup.1 represents an alkyl group having 1 to 6 carbon atoms; R.sup.2 represents an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 6 carbon atoms or a cycloalkyl group having 3 to 7 carbon atoms; and X represents --O-- or --NH--.
2. Related Art
Wounds are damages of surface tissues caused by surgical incision; gastrointestinal wounds or ulcer, burn induced by heat; UV rays or chemicals, ablation, lacerated wounds, amputation, wounds by pressure called "bedsore" or decubitus, erosion, etc. and infections. Particularly in patients who will receive surgical operation, their physical capability is generally declined seriously an most cases. It is thus desired to accelerate healing positively and directly, without relying only on natural healing of wounds. Turning to a bedsore, not only a patient himself suffers from pain but huge costs are required for healing such wounds. This appears to be a serious social problem as aged people increase. Healing of these wounds depends generally on the formation of new connective tissue and epithelial tissue due to cell growth and drugs that stimulate or promote the course of cell differentiation or cell growth included in the progress of healing wounds are considered to be very effective for the treatment.
As those showing an activity of promoting wound healing, there are known, as the effective ingredient, the extract of aloe, antibiotics, anti-inflammatory agents, kallikrein, adenine, nicotinic acid, allantoin, vitamin A, zinc, c-AMP derivatives (Japanese Patent Application KOKAI No. 107935/1988), exogenous DNA (Japanese Patent Application KOKAI No. 505888/1988), etc. The main trend was to improve pharmaceutical preparations in order to improve absorbability of these drugs as the effective ingredient. As various findings on dermatohistology were recently revealed, an attempt to use epithelial growth factor (b-EGF) for post-operative wound healing has also been reported (Japanese Patent Application KOKAI No. 106823/1991).
However, only a part of chemicals is effective in wound site by oral administration so that the effect is exhibited only with difficulty. In addition, there is a concern that Side effects might be caused. Accordingly, it is desired to use drugs for treatment which directly act on the skin topically to heal wounds. However, a few drugs for wound healing are known for topical use and make it difficult to heal wounds on the skin.
In general formula (I), compounds wherein R.sup.1 and R.sup.2 are isopropyl and X is oxygen are known to show action for accelerating wound healing when these compounds are orally administered [Journal of Showa Medical Association, vol. 42 No. 3, 293-300 (1982)]. However, the effect is equal to that of commercially available Solcoseryl in a dose of 1000 times that of Solcoseryl, meaning that the effect is far from its practical level. Taking it into account, the drug was not expected to be used for topical application.